A man cross-country skies in a field at the Notchview Reservation in Windsor, Massachusetts.

Courtesy of the trustees of reservations40850574http://extras.mnginteractive.com/live/media/site101/2014/1230/20141230__p_EAG-L-Calendar-0101~1.jpg6504334918740850577http://extras.mnginteractive.com/live/media/site101/2014/1230/20141230__p_EAG-L-Calendar-0101~1_100.jpg10067182940850578http://extras.mnginteractive.com/live/media/site101/2014/1230/20141230__p_EAG-L-Calendar-0101~1_200.jpg200133509940850579http://extras.mnginteractive.com/live/media/site101/2014/1230/20141230__p_EAG-L-Calendar-0101~1_300.jpg3002001020740850580http://extras.mnginteractive.com/live/media/site101/2014/1230/20141230__p_EAG-L-Calendar-0101~1_400.jpg4002661651840850581http://extras.mnginteractive.com/live/media/site101/2014/1230/20141230__p_EAG-L-Calendar-0101~1_500.jpg50033324329

A protective mother rests with her cub while scanning the Manitoba landscape for danger from male polar bears. See more of these images at the 'Lions, Tigers and Bears' exhibit at the Berkshire Museum through Jan. 4.